No, at this time it is not possible to add any lens to the current one NOR is it possible (short of taping one on) of adding a filter. I understand that an adapter is in the works and should come available in February so perhaps at that time you will be able to pursue an add-on lens. Personally, I wouldn't add anything on to this lens, given the fact that it already reaches to nearly 400mm (35 mm equivalent) and it becomes problematic to get sharp pictures at that telephoto reach but to each his own.